Katsuki didn’t know how this started—this thing between them. Not friendship. He could put a name to that. But this. The way they moved around each other like something that had always been there.

He was sitting on the edge of his bed, arms loose at his sides as the other boy knelt behind him, thumbs digging into the tight muscles between his shoulder blades.

He hadn’t even asked.

Not that Katsuki would’ve. But he didn’t have to.

“You’re very tense,” the other boy muttered, his fingers pressing into a knot of tension. “Do you even stretch?”

“Tch.” Katsuki rolled his eyes but didn’t pull away. “I do, dumbass.”

“Not enough,” came the easy reply. The boy’s hands were warm, pressing into his shoulders with just the right amount of pressure. Not too rough. Not too soft. Like he knew exactly how much Katsuki could take.

Which—yeah. Of course he did.

It had been like this for a long time now. Longer than Katsuki could remember.

They didn’t talk about it. They didn’t have to.

It was in the way Katsuki’s fingers would flick out before his brain even caught up, brushing crumbs from the other boy’s mouth when he ate too fast. The way the other boy would reach for his shoelaces when they came undone, crouching down without a word, tying them like it was second nature.

It wasn’t something they questioned. It wasn’t something they said.

“Fuck, that hurts,” Katsuki grunted as the other boy’s knuckles dug into the meat of his shoulder.

“That’s because you don’t stretch as much as you should,” the boy said, but his hands gentled, fingers dragging slower, softer over the ridges of Katsuki’s back.

Katsuki exhaled. His head dipped forward a little, his eyelids heavy. He could feel the heat of the other boy’s breath against his neck, close enough that if either of them moved just a little more—

But they didn’t.

Just like how they never talked about the way they moved around each other, like separate parts of the same whole.